<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        // 隐藏帧实现布局
        // 实际上iframe就相当于页面的子页面
    </script>
</head>
<body>
    <form action="./07-iframe.php" method="POST" target="myframe">
        用户名：<input type="text" name="username" id="">
        <span id="info"></span><br>
        密码：<input type="text" name="password" id=""><br>
        <input type="submit" value="登录">
    </form>
    <iframe src="" name="myframe" width="0" height="0" frameborder="0"></iframe>
</body>
</html>